I do also. However the most important thing I do is buy selectively. If I don't a have a REAL good idea on how I'd want to build a model, I don't buy it.
I have 53 kits. Only. And I'm quite happy with that number. It allows me to plan them without feeling overwhelmed. I know how I want to build them, I know what parts I need and a decent idea of what paints I'll need.
I've 32 un-started kits that are planned builds
6 kits bought for parts
3 kits available for trade
and 11 wips.
Buying on impulse, buying because it's a good kit, buying because it "might" come in handy. and buying multiples of the same subject (I have only one kit that I own multiples of) are all something to be avoided in my opinion. Getting overwhelmed by your own collection is caused by these things I think.